Keys that travel to actuate an underlying switch when pressed by a user typically provide for accurate user input and good tactile feedback to the user. In contrast, keys that do not travel such as keys on touch sensitive displays typically provide for less accurate user input and less tactile feedback to the user.
However, providing the space through which a key travels increases the volume of the keypad and the apparatus housing the keypad. This may be a disadvantage, particularly if the apparatus is a hand held apparatus where maintaining a small size is important.